Spectral analysis of changes in electroencephalographic activity after thechewing of gum

The present study aimed to examine the psychosomatic effect in the chewing of marketed gum using eletroencephalogram (EEG) as an index. The EEG were t aken in two sets: (i) a resting period before chewing (control recording) a nd a resting record (post-resting recording) for examining reproducibility; and (ii) a control recording and resting period after gum-chewing for 3 mi n (post-chewing recording). The ratio of each frequency band to the total f requency power, the mean frequency of the alpha band and laterality of the frequency power was calculated. In the examination of the reproducibility, no statistically significant differences were observed between control reco rding and post-resting recording in all indices. In the reflection of EEG a fter gum-chewing, there were no significant differences between control rec ording and the post-chewing recording. However, a significant interaction w as observed among these indices by analysis of variance. In addition, the a lpha power in the post-chewing recording was significantly higher than that in the control recording at almost all the positions. In conclusion, the i ntra-individual reproducibility of EEG was confirmed in the recording metho d. Furthermore, it was suggested that a significant interaction and a risin g trend of the mean frequency of the alpha band after gum-chewing reflected 'arousal' psychosomatic responses by the chewing of marketed gum.